For the compound AuCl3, the percent gold (Au) by mass is %? If you have a sample of 24.85 g AuCl3, the mass of gold in that sample is g?

Question

For the compound AuCl₃, the percent gold (Au) by mass is  %?

If you have a sample of 24.85 g AuCl₃, the mass of gold in that sample is  g?

Answer 1

atomic mass Au = 197

atomic mass Cl = 35.5

3 x 35.5 = 106.5 for Cl

1 Au = 197 for Au

Total molar mass of AuCl3 = 106.5 + 197 = 303.5 g/mol

% by mass Au = 197 / 303.5 (x100%) = 64.91% Au

Mass of Au in a 24.85 g sample = 24.85 g x 64.91% = 16.13 g Au